1. Field of the Invention
The present invention relates to a heating apparatus to be used in conjunction with outdoor surfaces such as driveways and walkways to prevent the accumulation of snow and ice.
2. Description of the Prior Art
Heating elements have been used in the past to warm walkways and driving surfaces to prevent the accumulation of snow and ice. Past configurations, although effective, are lacking in several respects as will become apparent in the discussion that follows.
One solution to the problem of snow and ice accumulation is shown in U.S. Pat. No. 4,564,745 issued Jan. 14, 1986 to Maurice Deschenes. This patented invention utilizes a flexible electric heating element embedded in a fiber-reinforced mortar, forming a heating panel. Although adequate in operation, the heating panels must be placed within the concrete that forms the walkway or driveway. This configuration, therefore, may only be implemented with surfaces and structures which have not yet been formed. As such, these heating panels cannot be used with already existing surfaces.
Another solution to the problem of snow and ice accumulation is shown in U.S. Pat. No. 2,912,555 issued Mar. 10, 1958 to Frederick W. Jamison. Disclosed in this patent is a heating coil contained in a slab of concrete again forming a heating panel. Once placed into position on a chosen surface such as a driveway, the panel is anchored to that surface with toggle bolts or screws to prevent shifting. While this configuration adequately melts snow and ice and can withstand the weight of a vehicle, the panels are both heavy and inflexible. The inflexibility of the panels creates difficulty in mounting the panels on uneven or angled surfaces. The weight of the concrete panels creates further difficulty for the user during set-up and removal of the panels. Due to the weight of the panels, they would be required to be in the form of small sections. Thus, many panels would be required to cover large surface areas, adding to the inconvenience of the configuration.
U.S. Pat. No. 4,967,057 issued Oct. 30, 1990 to Ronald E. Bayless et al. improves on the Jamison arrangement by providing small individual heating mats constructed of rubber rather than concrete. These mats, primarily intended for outdoor steps, have the advantage of being much lighter than concrete slabs. While these mats work well for heating small areas such as outdoor steps, it would be impractical to use such a configuration to heat larger areas such as driveways since several such panels would be needed, making set-up tedious. Moreover, if several such panels were used, there would be substantial potential for disconnection and/or separation of the panels when the panels are walked or driven upon. If the panels were made in larger dimensions to reduce the number needed to cover a large surface area, storage of the panels would then be difficult, large sections of thick rubber paneling being both somewhat inflexible and heavy.
Another arrangement for the prevention of snow accumulation is disclosed in U.S. Pat. No. 3,806,702 issued Apr. 23, 1974 to David R. Spencer. In this patent, a heating mat, again using an internal conductive heating element, also employs a temperature sensor and a precipitation sensor so that the apparatus may operate automatically once snow begins to fall. Similar to several other such heating devices, the outer covering of the mat is constructed of an electrically insulative material such as rubber. While quite practical for small applications, this configuration would also be highly impractical for larger applications such as a driveway since, as with the Bayless et al. patent teachings, a large mat would be both heavy and difficult to store. In addition, water pooling could occur if the mat was used on a level surface since no drainage means is provided.
Other such heating mats are shown in U.S. Pat. No. 2,619,580 issued Nov. 25, 1952 to Stanley M. Pontiere, U.S. Pat. No. 2,844,696 issued Jul. 22, 1958 to Byron K. Custer, Jr., and U.S. Pat. No. 3,143,641 issued Aug. 4, 1964 to Robert A. Wise.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.